The present invention is directed to a cable particularly a cable of optical waveguides in which the cable core of the optical transmission elements is surrounded by a covering or winding of tension supporting elements to relieve tension applied to the cable and the entire core and winding is covered by an external cladding or jacket.
An electrical or optical transmission cable, which has a core of transmission elements which is wrapped in a foil which carries tension supporting or resistant elements and is surrounded by an external plastic cladding or jacket, is known and an example is disclosed in German OS No. 28 18 297. In this arrangement, a series of connections are established between the interior of the cladding and each of the tensile supporting elements. To accomplish this, an additional or second foil is provided between the cladding and the tensile supporting elements and is either arranged to provide spaced exposure of the elements or has openings in the foil to expose the tension supporting elements. Thus, when the plastic cladding is extruded onto the additional foil which surrounds the tension supporting elements and core, the material of the cladding can come into contact with the tension supporting elements to form the spaced connections.
In the case of many sensitive cables, particularly in the case of optical waveguide cables or in the case of cables subjected to high tension forces, it happens that during a drawing-in operation such as drawing the cable during installation, the cladding is drawn in an axial direction a greater amount than the core. This is particularly true if the drawing-in operation utilizes a cable grip or a clamping operation on the end of the cladding to pull the cable in cable runs. Following termination of the drawing operation, the cladding, primarily in the end region, will again shrink back and thus exerts an upsetting or compressive force on the conductors or transmission elements of the cable core. This compressive force will result in an undesirable occurrence, particularly the formation of gaps, buckling or bending and the like. In the case of optical waveguide conductors, the buckling or bending can either lead to undesirable transmission behavior or damage the transmission behavior.